U.S. patent application number 10/155438 was filed with the patent office on 2002-10-03 for bedliner with anti-slip under layer.
Invention is credited to Emery, Phillip L..
Application Number | 20020140247 10/155438 |
Document ID | / |
Family ID | 22509576 |
Filed Date | 2002-10-03 |
United States Patent
Application |
20020140247 |
Kind Code |
A1 |
Emery, Phillip L. |
October 3, 2002 |
Bedliner with anti-slip under layer
Abstract
A truck cargo bed liner having an anti-slip under layer to
reduce rubbing between the liner and the cargo bed. The liner may
further include an upper layer of anti-slip material to resist
shifting of cargo during transport.
Inventors: |
Emery, Phillip L.; (Portage,
WI) |
Correspondence
Address: |
LATHROP & CLARK LLP
740 REGENT STREET SUITE 400
P.O. BOX 1507
MADISON
WI
537011507
|
Family ID: |
22509576 |
Appl. No.: |
10/155438 |
Filed: |
May 24, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10155438 |
May 24, 2002 |
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09144663 |
Sep 1, 1998 |
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6431629 |
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Current U.S.
Class: |
296/39.1 ;
296/39.2 |
Current CPC
Class: |
B60R 13/01 20130101 |
Class at
Publication: |
296/39.1 ;
296/39.2 |
International
Class: |
B60R 013/01 |
Claims
1. A truck cargo bed liner of unitary vacuum formed plastic having
a base sheet with an under side for engagement with a truck cargo
bed, comprising: a liner bottom; two liner wheel well covers formed
at opposite sides of the liner bottom; a liner front wall connected
to and extending upwardly from the liner bottom wall; two liner
side walls connected to the liner bottom wall and wheel wells and
the liner front wall at opposite sides thereof, each liner side
wall projecting upwardly from the liner bottom wall and adjacent a
wheel well cover; and an under layer having an effectively high
coefficient of friction joined to the under side of the base sheet
forming the liner.
2. The truck liner of claim 1, and further comprising: an upper
layer having an effectively high coefficient of friction joined to
an upper surface of the base sheet forming the liner.
3. The liner of claim 1, wherein the under layer was coextruded
with the base sheet forming the liner prior to vacuum forming the
liner.
4. The liner of claim 1, wherein the under layer was laminated to
the base sheet forming the liner by extrusion forming of the base
sheet prior to vacuum forming the liner.
5. The liner of claim 1, wherein the under layer was joined to the
base sheet forming the liner by an adhesive applied prior to vacuum
forming the liner.
6. The liner of claim 1, wherein the under layer was joined to the
base sheet forming the liner by a thermal attachment process prior
to vacuum forming the liner.
7. The liner of claim 1, wherein the under layer was joined to the
base sheet forming the liner by spraying under layer material on
the liner base sheet prior to forming the liner.
8. The liner of claim 1, wherein the under layer is joined to only
a portion of the underside of the liner base sheet.
9. The liner of claim 1, wherein the under layer is joined to
substantially all of the underside of the liner base sheet.
10. The liner of claim 1, wherein the under layer has a thickness
of not less than about ten thousandths of an inch.
11. The liner of claim 1, wherein the under layer is a composition
including very low density polyethylene and high molecular weight
high density polyethylene.
12. The liner of claim 1, wherein the under layer is a composition
including about sixty percent very low density polyethylene and
about forty percent high molecular weight high density
polyethylene.
13. The liner of claim 1, wherein the under layer is a composition
including polyolefin.
14. The liner of claim 1, wherein the under layer is a composition
including polyolefin selected from the group consisting of:
polyethylene; polypropylene; polybutylene; and polybutadiene.
15. The liner of claim 1, wherein the under layer is a composition
selected from the group consisting of: isocyanates; carbamates; and
ureas; and polymers and co-polymers thereof.
16. The liner of claim 1, wherein the under layer is a composition
including about sixty percent very low density polyethylene and
about forty percent polyolefin.
17. The liner of claim 1, wherein the under layer is a composition
including polyolefin in a range of about 30 to 50 percent
polyolefin.
18. The liner of claim 2, wherein the upper layer was coextruded
with the base sheet and the under layer.
19. The liner of claim 2, wherein the upper layer has a thickness
of not less than about forty thousandths of an inch.
20. The liner of claim 2, wherein the upper layer is a composition
including very low density polyethylene and high molecular weight
high density polyethylene.
21. The liner of claim 2, wherein the upper layer is a composition
including about sixty percent very low density polyethylene and
forty percent high molecular weight high density polyethylene.
22. The liner of claim 2, wherein the upper layer is a composition
including polyolefin.
23. The liner of claim 2, wherein the upper layer is a composition
including about sixty percent very low density polyethylene and
about forty percent polyolefin.
24. The liner of claim 2, wherein the upper layer is a composition
including polyolefin in a range of about 30 to 50 percent
polyolefin.
25. The liner of claim 1, wherein the liner base sheet includes a
high molecular weight high density polyethylene.
Description
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 09/144,663, filed Sep. 1, 1998, the disclosure
of which is incorporated by reference herein.
STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED
RESEARCH AND DEVELOPMENT
[0002] Not applicable.
BACKGROUND OF THE INVENTION
[0003] This invention relates to molded plastic protective liners
for pickup truck cargo beds, and in particular to liners with a
non-skid undersurface that protects truck beds from damage due to
rubbing by the liner.
DESCRIPTION OF THE PRIOR ART
[0004] Pickup trucks have been used for many years as working
vehicles. In recent years pickup trucks have become increasingly
popular as family transportation vehicles, because of their dual
ability to haul passengers and cargo. The cargo bed surfaces of
pickup trucks are generally finished with paint by the
manufacturer. If the painted surfaces are unprotected, they can be
scratched from cargo impact or deteriorated by weather or
corrosives, seriously detracting from the value of the trucks.
Whether a pickup truck is used as a working vehicle or as a family
transportation vehicle, it is important to keep the surface of the
cargo bed in a satisfactory condition.
[0005] Various cargo bed liners used to protect the surface of
cargo beds are described in prior art patents. One-piece molded
plastic truck liners comprising a front wall, opposing side walls
and a bottom wall are shown in U.S. Pat. Nos. 4,341,412 to Wayne;
4,336,963 to Nix et al.; 4,181,349 to Nix et al.; 4,047,749 to
Lambitz; 3,814,473 to Lorenzen; and 4,592,583 to Dresen. All of the
above patents show plastic liners that fit in the truck cargo bed
and bear on the bed floor, walls, and rails at various points of
contact, either by design or due to irregular liner shapes and
warping after the vacuum-formed manufacturing process. Where the
liner meets the cargo bed there may be rubbing because one-piece
molded plastic truck liners shift, particularly as the truck is
being loaded and unloaded, and as cargo shifts during transport. As
the liner shifts there may be rubbing on the surfaces of the truck
cargo bed that can scuff, scratch, and remove paint and paint
undercoats. When paint and paint undercoats are damaged, rusting of
the truck bed may occur thereby exposing the truck bed to corrosion
which adversely affects the appearance of the truck.
[0006] There are known truck cargo bed liners having anti-slip
upper surface for restraining cargo during transport, loading, and
unloading. The anti-slip surfaces comprise a layer having a higher
co-efficient of friction than the plastic forming the liner. (See:
U.S. Pat. No. 4,693,507, for example.) The non-slip layer may be
coextruded with, adhered to, or thermally attached to the plastic
base material before or during the liner vacuum forming process.
Although non-slip upper surfaces in bedliners are effective for
restraining cargo during transport, there is additional rubbing of
the under side of the HDPE base material against the truck cargo
bed because the cargo's weight shifts the cargo and the liner to
which it is now restrained.
[0007] A need exists for a one-piece plastic protective cargo bed
liner for engagement with at least a portion of the truck cargo bed
which will reduce damage to the cargo bed from rubbing by the
liners.
SUMMARY OF THE INVENTION
[0008] The present invention is a protective truck bed liner
adapted to reduce rubbing between the liner and the truck bed. The
liner includes an anti-slip under layer preferably made of a
plastic material that is either coextruded with or otherwise
adhered to a base sheet of plastic used to vacuum form the
liner.
[0009] The under layer has a coefficient of friction high enough to
reduce rubbing and thereby protect the truck cargo bed by reducing
damage due to the installation of the liner. The under layer can be
a composition including very low density polyethylene and very high
molecular weight high density polyethylene which can be in portions
of about sixty percent and forty percent, respectively. The under
layer may be a composition including a polyolefin and the
polyolefin may be between thirty and fifty percent of the
composition and is preferably about forty percent of the
composition. The under layer can be as thin as a single molecular
layer of anti-skid material and is preferably at least ten
thousandths of an inch thick. The under layer can be uniform
thickness or selectively applied to specific areas of the liner to
protect cargo bed components that are more susceptible to wear.
[0010] In addition, an upper anti-slip layer can be used and it can
be of the same composition as the under layer. The upper layer can
be as thin as a single molecular layer of anti-skid material and is
preferably at least approximately forty thousandths of an inch
thick.
[0011] It is an object of the invention to provide a plastic truck
cargo bed liner having an integral, durable anti-slip under
layer.
[0012] It is a further object of the invention to provide a plastic
protective truck cargo bed liner having an under layer that is
durable.
[0013] It is an additional object of the invention to provide a
plastic protective truck cargo bed liner having an anti-slip under
layer joined to at least a portion of the liner under surface.
[0014] Other objects, advantages and features of the present
invention will become apparent from the following detailed
description in conjunction with the accompanying drawings.
DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a perspective view of a cargo bed liner of the
present invention installed in a pickup truck.
[0016] FIG. 2 is a fragmentary sectional view taken substantially
along line 2-2 of FIG. 1.
[0017] FIG. 3 is a fragmentary sectional view of a cargo bed base
sheet sandwiched by anti-slip layers.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0018] FIG. 1 illustrates a conventional pickup truck 10 having a
cab 12 and a truck cargo bed 14. A preferred embodiment of the
protective truck cargo bed liner 16 of the invention is installed
within the truck cargo bed 14.
[0019] The truck bed liner 16 is typically formed from a base sheet
of high density polyethylene (HDPE) or high molecular weight high
density polyethylene (HMWHDPE) in a single, integral unit, and has
a liner bottom wall 18 which is adapted to fit on and substantially
cover the full width of the truck cargo bed floor. The liner bottom
wall 18 will normally have a width substantially as great as the
distance between the truck side rails. As shown in FIG. 2, the
liner bottom wall 18 typically contains a plurality of separate,
inverted U-shaped longitudinal corrugations 22. The bottom wall 18
also has a planar apron portion 70 at its rear margin which is
adapted to fit snugly against the truck cargo bed floor adjacent
the rear access opening 20 to keep foreign material from entering
between the liner and the truck bed.
[0020] The truck bed liner 16 also has two liner wheel wells 24
formed in the liner bottom wall 18 at opposite sides thereof. The
liner wheel wells 24 are adapted to accommodate the truck cargo bed
rear wheel wells (not shown). The liner wheel wells 24 have a top
wall 26, inside wall 28, and two opposing end walls, one end inside
wall 30 facing backward to the truck rear opening and one end wall
32 facing forward to the cab 12.
[0021] A liner front wall 34 is connected to and extends upwardly
from the liner bottom wall 18. As shown in FIG. 1, the liner front
wall 34 preferably contains structure such as a plurality of
vertically extending corrugations 36 for stability. The liner front
wall 34 has an upper margin 38 adapted to fit snugly against the
truck cargo bed front wall underneath the truck front rail 40.
[0022] Two liner side walls 42 are connected to the liner bottom
wall 18 and wheel wells 24 and also the liner front wall 34 at
opposite sides thereof. The liner front wall 34 substantially fixes
and limits the distance between the liner side walls 42 at the
front end of the liner 16. As shown in FIGS. 1 and 2, each liner
side wall 42 projects upwardly and outwardly from the liner bottom
wall 18 and adjacent liner wheel well 24. Each liner side wall 42
preferably has structure such as a plurality of corrugations 55 for
stability and an upper margin 44 which fits snugly against the
corresponding truck cargo bed wall 46 beneath the corresponding
truck cargo bed side rail 48. The upper margin 44 is preferably
substantially co-planar with the liner side wall 42 and may be
devoid of any substantial transverse flange to permit the side wall
42 to fit flush against the cargo bed wall 46, and also to permit
the liner side wall 42 to bend outwardly in a limited manner,
whereby the spacing of the side walls 42 near the front of the
liner will be maintained by the attached front liner wall 34, but
more rearwardly portions of the liner side wall 42 will be
permitted to open outwardly a limited amount when no restrained
within the truck cargo bed to facilitate full nesting of the liner
with identical liners.
[0023] It can be seen from FIG. 1 that pick-up cargo beds may have
two or three stake channels 76 spaced along each side rail 48, one
at each end and sometimes one at the mid-point. These stake
channels 76 are typically rectangular steel channels which extend
vertically downward from the top of the side rails 48 to the floor
of cargo bed, for the purpose of receiving stakes of wood or other
material supporting vertically extending sides for increasing the
load-containing capabilities of the truck cargo bed. Because the
preferred cargo bed liner 16 extends under the truck side rails 48
all the way to the truck cargo bed side walls, the stake channel 76
would interfere with the liner side walls 42 unless means are
provided to accommodate the stake channels 76. The liner side walls
42 intended for use in cargo beds with stake channels 76 preferably
each include a front pocket 78, a rear pocket 82, and , if
required, a side pocket 80. These side wall pockets 80 extend each
side wall 42 inwardly a sufficient distance to permit it to pass
around the stake channels 76 while permitting the remainder of the
side wall 42 to extend outwardly to engage the truck side wall 46.
The configuration of the side wall pockets 78, 80 and 82 may vary,
although preferably the pockets are located and shaped to
accommodate the differing stake channels of different truck cargo
bed manufacturers. As with the liner side wall and wheel well
surfaces, it is preferable to incline the surfaces of the pockets
to permit full nesting of the liners.
[0024] While the drawings illustrate a preferred truck cargo
bedliner 14 of the under rail type, the invention is equally useful
and advantageous when incorporated in a truck cargo bedliner of the
over rail type having flanges on the tops of the bedliner sidewalls
which extend over and rest on the truck side rails in a protective
manner. Examples of such over the rail type bedliners are
illustrated in above-mentioned U.S. Pat. Nos. 4,341,412; 4,336,963;
and 3,814,473.
[0025] A separate one-piece tailgate liner 72 may also be attached
to the tailgate of the truck in a conventional manner. The tailgate
liner 72 has inverted U-shaped, corrugations 74 which are
vertically extending when the tailgate is closed. The corrugations
74 are similar to the corrugations 22 of the liner bottom wall. The
tailgate liner 72 may also advantageously include anti-slip
frictional layers as described below.
[0026] The bedliner 16 of the present invention (FIG. 3) has an
undersurface that includes a base sheet 82 and an under layer 94 of
an anti-slip material that reduces or eliminates rubbing between
the liner 16 base sheet 82 and the cargo bed. The antislip under
layer 94 is preferably made of a material suitable for coextrusion
with the liner base sheet 82 plastic or otherwise bondable to or
with the liner base sheet 82 by adhesives or thermal bonding. In
any event, the under layer 94 must be securely joined to the liner
base sheet 82 either by mechanical means, chemical means, or
molecular interlocking between the anti-slip layer 94 and the base
sheet 82.
[0027] When bedliner sheets are produced using a coextrusion
process, the process beings with virgin plastic pellets or regrind
from scrap bedliner materials. The pellets and/or regrind are
conveyed through heated barrels by rotating screws to extrude
barrels that melt the pellets and/or regrind and feeds the melted
plastic in streams that converge at a die block.
[0028] Different blends of materials are fed through separate
extruders to create an anti-skid or "softer" material in one layer
to become the liner under layer, and a liner base sheet 82 of HDPE
or HMW-HDPE. If a skid-resistant upper or interior layer 84 is
desired, a third material or the same anti-skid material used in
the under layer 94 can be diverted in the die block to sandwich the
HDPE material in the liner base sheet 82.
[0029] As the materials melt in the heated barrels, they are fed
through the die block and exit to be shaped into a continuous
monolithic shape or sheet by steel rolls, such as embossing chrome
rolls. The sheet cools and the outer edges are trimmed to size. The
sheet is cut to length in a chopper and then stacked and stored
before being used in a vacuum forming process to form a liner of a
desired shape.
[0030] The thickness of the sheet and the individual coextruded
layers are adjustable in the process. For example, a 230
thousandths of an inch thick sheet preferably has a ten thousandths
of an inch under layer 94, a 180 thousandths of an inch base sheet
82, and a 40 thousandths of an inch interior or upper layer 84 for
contacting cargo. The layers can be extremely thin and still
provide anti-slip properties. Layers as thin as a single molecule
thick can provide the desired properties. These thicknesses are
approximated over the sheet area because the thermoforming process
used to form the bedliner 16 will stretch the sheet and vary the
material thickness depending on the draw conditions and final
deposit location.
[0031] As stated, the base sheet 82 is typically HDPE, HMW-HDPE, or
other "stiff" material to provide the liner 16 with structural
integrity and impact resistance. The anti-slip upper and under
layers 84 and 94 provide resistance to shifting cargo and rubbing
of the cargo bed. The anti-slip layers 84 and 94 also provide
impact absorbance and have a good appearance.
[0032] Preferably, the anti-slip layers 84 and 94 are about 60
percent very low density polyethylene (VLDPE), about 40 percent
high molecular weight high density polyethylene (HMW-HDPE), and a
small amount of colorant. The base sheet 82 is preferably 30 to 100
percent HMW-HDPE, zero to 70 percent (for an average of about 40%)
regrind from the trimming process, and a small amount of colorant.
These percentages are by weight. In the base sheet 82, the
percentages fluctuate due to the available amount of regrind which
contains various percentages of the materials used in the various
layers, including small amounts of VLDPE.
[0033] A suitable HMW-HDPE is Fortiflex.RTM. G50-100 available from
Solvay Polymers, Inc., 3333 Richmond Avenue, Houston, Tex.
77098-3099. A suitable VLDPE is Flexomer.RTM. Polyolefins,
DFDB-1085 Natural, available from Union Carbide Corporation, Unipol
Polymers, 39 10d Ridgebury Rd., Danbury, Conn. 06817-0001. Such a
polyolefin is a semicrystalline ethylene copolymer with elastic
properties approaching those of uncured EPM and EPD rubbers to
serve as an impact modifier for polypropylene.
[0034] The thickness of the under layer 94 can be discontinuous or
otherwise modified at various points or areas on the sheet to
reduce cost and concentrate antiskid materials at locations where
rubbing is of greater concern due to likelihood of corrosion and
affect on appearance if the liner is removed. Areas of greater
concern include; the cargo bed floor, the truck rails, and the
front wall. In areas of less concern, such as side walls where
there is little or no liner-to-wall contact, there need not be any
anti-skid material. Nonetheless, when using the coextrusion
process, the layers are as uniform as practical and cover the
entire sheet. Alternatively, the under layer 94 can be sprayed on
using known methods which result in a discontinuous layer of
hardened bubbles or droplets that form a textured surface. Known
spray-on materials include: isocyanates; carbamates; ureas; and
polymers and co-polymers of these materials.
[0035] As stated above, the inside surface 54 of the cargo bed
liner 16 is preferably provided with an integral anti-slip surface
made of an upper frictional layer 84. The upper layer 84 has a high
coefficient of friction that will inhibit movement of material
placed on the upper surface of the liner 16 during use. The upper
layer 84 may be laminated to the upper surface of the base sheet 82
of the liner 16 during extrusion forming of the sheet prior to
vacuum forming of the liner. In addition to the mix described
above, suitable materials for the anti-slip layers include ethylene
ethyl acetate (EEA), ethylene vinyl acetate (EVA), thermoplastic
rubber (TPR), Saranex, and a modified polyolefin sold under the
trademark Ren-Flex by the Ren Plastics Company. The film may be
adhered to the base sheet 82 by an adhesive or by thermal
attachment during the liner vacuum forming process.
[0036] Optionally, a blend of a thermoplastic rubber material sold
under the trademark Kraton by Shell Oil Company, Woodbury, N.J.,
and a thermoplastic rubber material sold under the trademark
Santoprene by Monsanto Polymers Division of Monsanto Chemical
Company, St. Louis, Miss. is coextruded as a film between
approximately 10 and 35 thousandths of an inch thickness, such as
25 to 30 thousandths of an inch thick on at least portions of the
liner upper surface. A preferred blend of Kraton and Santoprene in
the film in approximately equal portions provides desirable
anti-slip characteristics without being tacky. These and other
features are disclosed in U.S. Pat. No. 4,693,507, which is
incorporated herein by reference.
[0037] While the anti-slip frictional layers 84 and 94 have been
illustrated and described on a preferred plastic truck body liner,
it is understood that the anti-slip frictional layers of the
invention may be incorporated in thermoformed plastic truck bed
liners of any desired shape or style.
[0038] It is understood that the invention is not confined to the
particular construction and arrangement of parts herein illustrated
and described, but embraces such modified forms thereof as come
within the scope of the following claims.
* * * * *